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Query: UMLS:C0020538 (hypertension)
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We have investigated the cellular basis for the clinical and epidemiologic linkage of hypertension, left ventricular hypertrophy (LVH), obesity, and non-insulin-dependent diabetes mellitus (NIDDM) and have studied cytosolic free calcium and free magnesium levels in these syndromes. Specifically, intracellular free calcium is elevated and free magnesium is deficient in hypertension, and both are related (directly and inversely, respectively) to the ambient level of blood pressure, to LV mass index (and thus to the degree of cardiac hypertrophy), and to the hyperinsulinemia and insulin resistance of essential hypertension. Dynamically, the ability of dietary salt loading to elevate blood pressure corresponds to its ability to elevate cytosolic free calcium and reciprocally to suppress free magnesium levels. Conversely, the ability of calcium channel blockade to reverse salt-induced hypertension is related to its ability to prevent these transmembrane ionic effects. Higher steady-state free calcium or lower free magnesium, or both, are also observed in clinical states linked to hypertension, such as obesity and NIDDM. Oral glucose loading in normal subjects itself elevates free calcium and suppresses free magnesium levels, as does hyperglycemia in vitro. These data suggest an ionic hypothesis of cardiovascular and metabolic disease, in which a generalized defect in cell ion handling is present in all tissues, resulting in higher steady-state free calcium and lower free magnesium levels. In pancreatic beta cells, this would produce hyperinsulinemia; in fat and skeletal muscle, cause peripheral insulin resistance; and in renal tissue, increase proximal sodium resorption and increase urinary calcium excretion--all features of essential hypertension. In vascular smooth muscle, high cytosolic free calcium would increase smooth muscle tone and cause vasoconstriction, and in heart muscle, independent of blood pressure, would increase contractility and predispose to LVH. Therefore, what may appear clinically to be the separate syndromes of hypertension, obesity, and NIDDM may pathophysiologically be different manifestations of the same underlying cellular defect, thus explaining their frequent clinical coexistence. Therapeutically, reversal of this excess free calcium accumulation and/or free magnesium deficit with ion-specific agents, such as calcium channel blocking drugs, may thus ameliorate not only the elevated blood pressure of hypertension but also the concurrent excess morbidity and mortality of the concurrent cardiac, vascular, and metabolic aspects of the hypertensive state.
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PMID:Cellular calcium and magnesium metabolism in the pathophysiology and treatment of hypertension and related metabolic disorders. 138 62

Finding the proper balance between too much and not enough immunosuppression is just as important in the late posttransplant period as it is during the first year after transplantation. In general, too much immunosuppression leads to an increase in patient mortality, whereas inadequate immunosuppression can lead to an inordinately high rate of allograft failure (Fig 5). In the late posttransplant period, patient and allograft survival are both critically dependent on the degree of immunosuppression and on the long-term side effects of the agents used to achieve this immunosuppression. Adequate immunosuppression is important in treating and preventing the acute allograft rejection episodes that are common during the first year after transplantation (Fig 6). Some data suggest that the severity of early acute rejection episodes may influence the development of chronic rejection, the most common cause of graft failure in the late posttransplant period. Otherwise, the role of immunosuppression in treating and preventing chronic rejection is unclear. The discontinuation of immunosuppression by noncompliant patients is a major cause of late graft failure. Whether the nephrotoxicity of CsA will also result in graft failure in the very late posttransplant period is still unknown. The agents used to achieve immunosuppression, along with decreased graft function and proteinuria, contribute to hypercholesterolemia, hypertension, and hyperglycemia. These and other risk factors have a negative impact on both graft and patient survival. Thus, immunosuppression is directly, or indirectly linked to most of the common causes of death and graft failure after renal transplantation. Although potent new immunosuppression protocols have increased the rate of short-term patient and allograft survival after renal transplantation, future advances in long-term survival after renal transplantation will depend on improvements that are effective in the late posttransplant period. Currently, the best approach to preventing complications in the late posttransplant period is to maintain a vigilant, comprehensive program of on-going medical care. The minimal amount of immunosuppression required to prevent allograft rejection should be used, while adhering to the principle that it is better to lose the graft than to lose the patient.
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PMID:Patient and renal allograft survival in the late posttransplant period. 141 Aug 62

The records of 150 consecutive patients undergoing thoracoabdominal aortic replacement from 1980 to 1991 were retrospectively reviewed. There were 89 men and 61 women; mean age was 67.8 years (range: 33 to 88 years). Since June 1989, a multimodality prospective perioperative protocol was used to reduce the risk of spinal cord dysfunction. Ischemia is minimized by complete intercostal reimplantation whenever possible, cerebrospinal fluid drainage, and maintenance of proximal hypertension during cross-clamping. Spinal cord metabolism is reduced by moderate hypothermia, high-dose barbiturates, and avoidance of hyperglycemia. Reperfusion injury is minimized by the use of mannitol, steroids, and calcium channel blockers. Ninety-seven percent of patients survived long enough for evaluation of their neurologic function. Spinal cord dysfunction was reduced from 6 of 108 (6%) in the preprotocol group to 0 of 42 in the protocol group (0%) (p less than 0.01). The overall 30-day operative mortality was not significantly different between the groups (9% versus 12%, p = NS). A multimodality protocol appears to be effective in reducing the risk of spinal cord injury during thoracoabdominal aortic replacement.
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PMID:Risk of spinal cord dysfunction in patients undergoing thoracoabdominal aortic replacement. 141 16

During the past decade, the morbidity and mortality associated with cardiac transplantation have decreased dramatically. The current survival for patients who undergo orthotopic cardiac transplantation is 80 to 90% at 1 year and 70 to 80% at 5 years; these results are attributed chiefly to improved immunosuppression and the consequent decrease in infectious illnesses and rejection. Because surgical mortality and technique have not changed appreciably during the past 20 years, improved survival can be ascribed to advances in the medical management of recipients of cardiac transplants. Medical problems frequently encountered in such patients include allograft rejection, allograft vasculopathy, hypertension, renal dysfunction, hyperlipidemia, hyperglycemia, malignant disorders, general surgical disease, and osteopenic bone disease. Hence, the expertise needed for management of patients who undergo cardiac transplantation is not confined to a particular specialty--optimal care necessitates the integrated efforts of a team, including transplant physicians and personnel to provide broad subspecialty and laboratory support. Meticulous management with proactive intervention and minimal effective immunosuppression will prevent or ameliorate many problems and contribute to increased survivorship and improved quality of life. For additional substantive improvement in long-term survival and quality of life for recipients of cardiac allografts, multicenter, prospective, and placebo-controlled clinical investigations will be necessary.
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PMID:Management of patients after cardiac transplantation. 143 17

An increased risk of developing premature atherosclerosis is associated with stress, diabetes, obesity, and hypertension. These conditions are associated with insulin resistance, hyperglycemia, hypertriglyceridemia and hypercholesterolemia. An alternative way of interpreting insulin resistance is to consider that metabolism in this condition would be regulated to a greater extent by stress hormones and in particular by cortisol. Glucocorticoids and fatty acids (which are produced in response to stress) antagonise the actions of insulin in promoting glucose uptake and protein synthesis, in decreasing gluconeogenesis and protein catabolism, and promoting the clearance of intermediate density lipoprotein and low density lipoprotein from the circulation by the liver. They also promote the secretion of very low density lipoprotein thus producing hypertriglyceridemia and hypercholesterolemia. By contrast to this antagonism, cortisol can also facilitate the action of insulin in stimulating the storage of energy via glycogen and fatty acid synthesis and through lipoprotein lipase in adipose tissue. These effects are significant in relation to obesity and to weight gain. An increased control of metabolism by cortisol therefore produces changes in metabolism that are potentially atherogenic and it is associated with insulin resistance and the other risk factors for atherosclerosis. Benfluorex treatment improves insulin sensitivity and has antihyperglycemic and hypolipidemic effects in human beings and in experimental animals. These effects can be observed independently of weight loss, but lowering food intake also produces a metabolic benefit. Long-term treatment with benfluorex can also decrease stress responses in terms of glucocorticoid release and the stimulation of lipolysis probably by its serotoninergic control of the hypothalamic-pituitary-adrenal axis. Such an action provides for an integrated treatment of the obese-diabetic-hyperlipidemic syndrome. Benfluorex produces overall changes in metabolism that tend to normalise the major risk factors associated with premature atherosclerosis. This provides a potential advantage over other therapies for atherosclerosis which may ameliorate a symptom (e.g., hyperlipidemia) without treating the underlying metabolic disturbance that predisposes to atherogenesis.
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PMID:[Mode of action of benfluorex. Recent data]. 143 2

BACKGROUND--Thirty-five percent of type I-diabetic patients are dead of coronary artery disease by age 55 years, and the risk of death is increased eightfold to 15-fold in patients with nephropathy. However, the prevalence of coronary artery disease with respect to age is unknown and few risk factors have been identified. METHODS--One hundred ten insulin-dependent diabetic patients underwent routine pretransplant coronary angiography and cardiac risk factor assessment. Angiograms were evaluated by two angiographers for presence or absence of coronary artery disease (CAD, defined as one or more coronary artery stenoses of 50% or greater in diameter, and no CAD, defined as no stenosis of 25% or greater in diameter, respectively). Prevalence of CAD by age was determined, and associated risk factors were defined. RESULTS--Fifty-two of 110 patients had CAD. Coronary artery disease prevalence increased significantly with age; 13 of 16 patients older than 45 years of age had CAD. For patients 35 years of age or younger, associated risk factors included a family history of premature myocardial infarction, higher hemoglobin A1c level, hypertension for more than 5 years, lower high-density lipoprotein level, and smoking for more than 5 pack-years. For patients between 35 and 45 years of age, associated risk factors included number of years of diabetes, higher hemoglobin A1c levels, and smoking more than 5 pack-years. CONCLUSIONS--In type I-diabetic patients with nephropathy, CAD prevalence increased significantly with age and was found in the majority of patients older than 45 years of age. Coronary artery disease risk factors operative in the general population were significantly associated with CAD in this high-risk group. In addition, a role for hyperglycemia in accelerated atherogenesis was supported by the association of both higher hemoglobin A1c levels and number of years of diabetes with CAD.
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PMID:Prevalence of, and risk factors for, angiographically determined coronary artery disease in type I-diabetic patients with nephropathy. 145 56

The aim of this study was to evaluate the prevalence of arterial hypertension and other risk factors in patients suffering from peripheral arterial disease (PAD) in two clinical samples (1.: 102 patients with PAD 69 M, 33 F, studied in our angiology laboratory, matched for sex and age with 102 healthy volunteers; 2.: 184 hospitalized patients, 80 M, 104 F, mean age 57.2 +/- 10.8, with PAD) and in two epidemiological cohorts (1.: Trabia Study, 835 subjects; 2.: Casteldaccia Study, 723 subjects). All patients were subjected to a full clinical and laboratory examination, including the determination of the ankle/arm pressure ratio (Winsor index, positive for PAD when lower than 0.95). In the first clinical study we observed a significantly (p < 0.01) greater prevalence of arterial hypertension (51.9 vs 9.8%), hypercholesterolemia (48.2 vs 21.6%), hypertriglyceridemia (53.7 vs 26.1%), smoking habit (64.3 vs 44.2%), and hyperglycemia (26 vs 7,9%) in PAD patients than in controls. In the second clinical study considering separately the patients under and over 65 years, all risk factors resulted to be more prevalent in younger people than in the aged, except for diabetes and hypertension. In our epidemiological experience, the prevalence of PAD increases with aging, above all in males. In the Trabia Study the risk factors, more associated with PAD, were hypercholesterolemia, smoking and obesity (41.18%) in males and hypertension and hypercholesterolemia (33.3%) and obesity (25%) in females. In the Casteldaccia Study the most important risk factors were smoking (64.28%), hypercholesterolemia (42.86%) and hypertriglyceridemia (35.71%) in males, and obesity (60%), hypercholesterolemia (30%) and diabetes (20%) in females. Cholesterol levels and smoking were significantly higher in PAD patients than in the general population, whereas hypertriglyceridemia and glycemia were not. Arterial hypertension was significantly associated with PAD in the Trabia but not in the Casteldaccia Study. Obesity was significantly associated to PAD in females in both studies. In the Casteldaccia Study, lower HDL-cholesterol levels were observed in PAD patients, above all in males, whereas significantly greater Apo-B values and lower Apo-A1 levels (in males) were shown. The different levels of associated risk factors and their prevalence in PAD patients confirm the multifactorial pathogenesis of atherosclerosis. The exact role of each risk factor in the genesis of PAD is difficult to be evaluated due to the complex biological and statistical interrelationships among different risk factors. However, the management of associated risk factors may favourably influence the risk profile in each patient suffering from PAD.
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PMID:Prevalence of risk factors in patients with peripheral arterial disease. A clinical and epidemiological evaluation. 146 Mar 57

Myocardial performance of streptozotocin (STZ)-diabetic deoxycorticosterone acetate (DOCA)-hypertensive rats was examined using the isolated working heart apparatus at various time periods after induction of the experimental diseases. Blood pressure, pulse rate, and plasma levels of glucose, insulin, cholesterol, and triglycerides, as well as ventricular weight-to-body weight ratio, were also determined. In nondiabetic rats it was found that DOCA hypertension was associated with an increase in plasma cholesterol, a decrease in circulating insulin level, lower weight gain, and ventricular enlargement compared with control rats. Diabetic rats developed myocardial dysfunction in a time-dependent manner and exhibited hyperglycemia, hypoinsulinemia, bradycardia, and ventricular enlargement. Compared with the normotensive diabetic animals, STZ-diabetic DOCA-hypertensive rats showed a similar magnitude of myocardial dysfunction and a greater degree of ventricular enlargement, but significantly less severe hyperglycemia. It is concluded that DOCA-induced hypertension does not aggravate the severity of myocardial dysfunction developed in STZ-diabetic rats. It is also suggested that DOCA may have an action on glucose metabolism either directly or via an effect on insulin secretion.
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PMID:Myocardial performance of STZ-diabetic DOCA-hypertensive rats. 148 3

Patients with diabetes mellitus are at increased risk of morbidity and mortality from macrovascular disease manifesting as coronary heart disease, cerebrovascular accidents, and peripheral vascular disease. Increased frequency of dyslipidemia, hyperglycemia, obesity, hypertension, and associated nephropathy may contribute to accelerated atherogenesis in diabetic patients. Therefore, besides intensive control of hyperglycemia, management of dyslipidemia, hypertension, and obesity should also be emphasized in diabetic patients. Those who smoke should be strongly encouraged to quit smoking. Besides attempts to achieve normal levels of plasma lipoproteins, consideration also should be given to normalization of compositional abnormalities of various lipoproteins in patients with diabetes mellitus. The therapeutic goals for cholesterol reduction should be lower in diabetic patients than nondiabetic subjects. The first step is to achieve good metabolic control of diabetes mellitus by diet, exercise, and weight reduction and, if needed, with sulfonylureas or insulin therapy. Because most of the patients with insulin-dependent diabetes mellitus achieve normal levels of plasma lipoproteins with intensive insulin therapy, lipid-lowering medications are rarely needed. In patients with non-insulin-dependent diabetes mellitus, however, dyslipidemia often persists despite good glycemic control. Lipid-lowering medications should be considered in such patients. Because nicotinic acid can cause marked deterioration in glycemic control, and bile acid-binding resins may accentuate hypertriglyceridemia, these agents are less desirable for use by diabetic patients. Inhibitors of hydroxymethylglutaryl coenzyme A reductase may be preferred in patients with elevated LDL cholesterol and mld hypertriglyceridemia. For diabetic patients with marked hypertriglyceridemia, however, fibric acid derivatives should be the drug of choice.
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PMID:Lipid-lowering therapy and macrovascular disease in diabetes mellitus. 152 29

By the term "insulin resistance" we understand the attenuation of insulin-stimulated glucose uptake, which is mainly due to attenuated glycogen synthesis in skeletal muscle and is partially compensated with regard to plasma glucose homeostasis by hyperinsulinemia. Other mechanisms of insulin are either not attenuated or are less so and may contribute via hyperinsulinemia to the prevalence of hypertension, obesity, dyslipoproteinemia and type-II diabetes. At the level of insulin receptors, resistance can be due to muscle-specific, preferential expression of the low-affinity B-isoform of the insulin receptors. In rare cases of extreme resistance, it can also be due to several mutations at the insulin receptor gene or due to insulin-receptor autoantibodies. At the postreceptor level, the translocation and or expression of the insulin-responsive glucose carrier GluT-4 can be down-regulated via the hexosamine pathway by hyperglycemia plus hyperinsulinemia. Furthermore, Glut-4 can be inhibited and/or down-regulated by sustained insulin deficiency, partially via c-AMP-dependent pathways. Additionally, the insulin-induced glycogen synthesis in skeletal muscle can be attenuated by the endogenous peptides amylin and calcitonin-gene-related peptide, and by modulations of endothelial function, perfusion and capillary recruitment in the microcirculation of skeletal muscle. Epidemiological data indicate a genetic predisposition for insulin resistance. However, among the many mechanisms potentially contributing to the complex syndrome of insulin resistance, no specific localization of that predisposition can be proposed at present.
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PMID:[The mechanisms of insulin resistance]. 153 3


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